DIFF: Allegro - fbconfig supports translucent windows

@@ -234,6 +236,10 @@ static ALLEGRO_EXTRA_DISPLAY_SETTINGS** get_visuals_new(ALLEGRO_DISPLAY_XGLX *gl

    ALLEGRO_INFO("%i formats.\n", num_fbconfigs);

+   Display *dpy = system->gfxdisplay;
+   XVisualInfo *visual;
+   XRenderPictFormat *pict_format;
+
    for (i = j = 0; i < num_fbconfigs; i++) {
       ALLEGRO_DEBUG("-- \n");
       ALLEGRO_DEBUG("Decoding visual no. %i...\n", i);
@@ -243,6 +249,23 @@ static ALLEGRO_EXTRA_DISPLAY_SETTINGS** get_visuals_new(ALLEGRO_DISPLAY_XGLX *gl
 #ifdef DEBUGMODE
       display_pixel_format(eds[j]);
 #endif
+
+      visual = (XVisualInfo*) glXGetVisualFromFBConfig(dpy, fbconfig[i]);
+      if (!visual) {
+         al_free(eds[j]);
+         continue;
+      }
+
+      pict_format = XRenderFindVisualFormat(dpy, visual->visual);
+      if (!pict_format) {
+         al_free(eds[j]);
+         continue;
+      }
+      if (pict_format->direct.alphaMask <= 0) {
+         al_free(eds[j]);
+         continue;
+      }
+
       eds[j]->score = _al_score_display_settings(eds[j], ref);
       if (eds[j]->score == -1) {
          al_free(eds[j]);